Yes totally normal as others have said. If upkeep testing it will go back to the same as the control after a little while longer, then finally it will return to being fainter than the control line like when u first start testing. it's called the hook effect, the test can't cope with such high levels of hcg. I tested it out today and found it really interesting, I had to add 75% water to the wee sample to get the test line to go darker than the control again.